This invention relates to sailboats and in particular to a new and improved hull form.
The action of air on a sailboat's sails exerts a tilting force sideways on the sailboat. In sailing terms, the tilt is called the sailboat's heel. Sailboat designers take heeling into account when designing boats and generally design for maximum performance at a given heel. Sailboat designers accomplish this through a combination of hull shaping and ballasting. A traditional hull shape will have the center portion protruding in a fin-like fashion vertically downwards. In a small sailboat, a dagger board protruding vertically downwards through the center of the hull is often used. A traditional hull shape provides lateral resistance in the water to any sudden tilting forces as may be caused by a sudden wind gust or changeable water conditions. The hull shape also minimizes yaw and provides excellent handling conditions under a wide range of air and sea conditions. To offset the underlying tilting forces exerted by constant and steady winds, ballast is used in the hull. The ballast is generally concentrated in the downward protrusion of the hull. The ballast below the waterline is meant to offset the weight of the mainmast, sails, rigging and the forces exerted on them by the wind and sea. In theory, therefore, heel is controlled for a wide range of air conditions by hull shaping and ballasting.
Sailboats, however, are inherently unstable due to their narrow beams. They still capsize despite the best efforts of sailboat designers to add stability. Many boat designs have been put forth to increase sailboat stability. Multihull boats such as catamarans and trimarans are common. Outriggers and pontoons have been used for years. These types of boats, while stable, tend to be difficult to hold on the vertical axis and can be difficult to handle in high seas. Another approach has been the use of rear horizontally extending fins such as disclosed in U.S. Pat. No. 2,218,264 to H. H. Luce. A similar approach is used in the Mexican styled "Pangas". Pangas are open displacement boats twenty to thirty feet in overall length, with a pair of porpoise-like fins that sprout laterally from the boat's skeg a few inches below the waterline. An inherent limitation in the use of rearward horizontal fins on a boat is the tendency of the boat to leap frog during high seas or high speeds. Although the above design approaches, i.e., muliple hulls, pontoons, rearward horizontal fins, etc., add stability to a sailing craft, the handling ability of a traditionally designed, single hull sailboat in a wide range of weather conditions is sacrificed.